On site application of paint directly to a surface to be decorated is the time-honored method for providing a graphic design, such as a decorative design. While such a process provides many aesthetic and physical features, including realistic appearance, color flexibility, durability to abrasion, weathering and chemical attack, it also suffers from many disadvantages. For example, relatively skilled labor is necessary. Long application times are usually the rule, and potential contamination to adjacent areas, particularly mechanical equipment, can occur. Accordingly, prefabricated film graphics have been utilized to avoid many of these disadvantages. Such film graphics, often called "decals" or "transfer graphics", when utilized on the exterior surface of vehicles, typically require extreme resistance to abrasion and chemical attack because of exposure of the vehicle surfaces to various atmospheres or environments. Accordingly, such graphics must generally be provided with a protective clear coat over the graphic areas.
This protective clear coat can be located in registry with the graphic area by applying a continuous layer of clear coat over the graphic and non-graphic areas, and subsequently cutting through the several layers precisely at the outline of the graphic area, typically called "die cutting" or "kiss cutting". This approach can result in considerable waste, and furthermore can require rather expensive cutting tools, particularly if intricate graphic designs are involved. Furthermore, the vertical or right angle edges of the graphic and protective clear coat can collect dirt, wax and other foreign materials which can detract from the aesthetics of the applied graphic design.
A second approach is to apply the protective clear coat only to graphic areas, as, for example, by screen printing, utilizing a stencil with an open area corresponding precisely to the outline of the graphic design. Those skilled in the art are aware of the difficulty encountered with such a process, because of factors such as dimensional changes in the film substrate, tension variables in the screen mesh, and accurate positioning of the substrate in registry with the stencil. Small graphics, such as those with overall dimensions of not greater than 12".times.12" can generally be manufactured with satisfactory registration by those having requisite skill. However, this becomes much more difficult for larger graphic areas, and particularly for decorative items such as pin stripes which are common for the vehicle or automotive market.
Yet another approach which has been utilized is to apply the protective clear coat with a substantial oversize border to assure complete coverage of the graphic area. While this method achieves the required objective of protection for the graphic design, it is generally considered not to be aesthetic.
Although application of a protective clear coat by screen printing is a typical technique, other methods such as roller coating or spray coating may also be considered, providing a dry film thickness of about 0.6 mils is achieved.
Summarizing, an acceptable protective clear coat should be of sufficient thickness to provide adequate wearability and resistance to chemical environments, precisely cover the graphic area, whether same be large or small, and whether it be a simple geometric shape, such as a narrow width line, or a complex intricate design. Known techniques described above do not satisfy all these requirements.
Accordingly, the present invention provides exact registration of a clear protective coat over a graphic image; the protective coat has tapered, rounded and sloping edges which inhibits the buildup of wax and foreign matter at the edge portions, and looks integrated with the substrate; i.e., a paint-like look; the process can accomodate varying process tolerances, operator variability and equipment tolerances; the process provides a lenticular appearance on thin pin stripes, such as may be placed on vehicle surfaces; no kiss cutting or die cutting of the graphic is required; the graphic is defined by the printed graphic image, and the detail thereof is restricted to the image detail.